## BART D ETERMINATION 

## R EPORT 

## A MERICAN 

## E LECTRIC 

## P OWER 

##  C OMANCHE 

## P OWER 

## S TATION 

## U NITS 

## 1 AND 

## 2

Prepared by:

N.N. Dharmarajan  AEP

Vern Choquette  Principal Consultant Eugene Chen, PE  Senior Consultant Jeremy Townley  Consultant

T RINITY C ONSULTANTS 120 E. Sheridan Suite 205 Oklahoma City, OK 73104 (405) 228-3292

August 2008

Project 083701.0057AEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 i 

## T ABLE OF 

## C ONTENTS



### 1. E XECUTIVE 

### S UMMARY 

### ........................................................................................ 1-1

2. B ACKGROUND 

### ...................................................................................................... 2-1 2.1 BART A PPLICABILITY 

### .......................................................................................... 2-1
2.1.1 CALPUFF M ODELING A NALYSES ......................................................................2-3 

### 2.2 BART D ETERMINATION 

### ....................................................................................... 2-3

3. BART A PPLICABILITY 

### A NALYSIS 

### ...................................................................... 3-1 3.1 BART-E LIGIBLE 

### S OURCES 

### ................................................................................... 3-1 3.2 S OURCE 

### E MISSIONS 

### D ATA 

### .................................................................................... 3-1
3.2.1 PM E MISSIONS ....................................................................................................3-2
3.2.2 S TACK PARAMETERS ...........................................................................................3-2



### 4. SO 2 

### BART D ETERMINATION 

### .............................................................................. 4-1 4.1 I DENTIFICATION OF 

### A VAILABLE 

### R ETROFIT 

### SO 2 

### C ONTROL 

### T ECHNOLOGIES 

### .......... 4-1

5. PM BART D ETERMINATION 

### .............................................................................. 5-1 5.1 I DENTIFICATION OF 

### A VAILABLE 

### R ETROFIT 

### PM C ONTROL 

### T ECHNOLOGIES 

### ........... 5-1

6. NO X 

### BART D ETERMINATION 

### .............................................................................. 6-1 6.1 I DENTIFY 

### A LL 

### A VAILABLE 

### R ETROFIT 

### T ECHNOLOGIES 

### .......................................... 6-1 6.2 E LIMINATE 

### T ECHNICALLY 

### I NFEASIBLE 

### O PTIONS 

### .................................................. 6-1
6.2.1 D RY L OW NO X B URNERS (DLNB).....................................................................6-2 

### 6.3 E VALUATE 

### E FFECTIVENESS OF 

### R EMAINING 

### C ONTROL 

### T ECHNOLOGIES 

### ................ 6-2 6.4 E VALUATION OF 

### I MPACTS FOR 

### F EASIBLE 

### NO X 

### C ONTROLS 

### ................................... 6-2
6.4.1 C OSTS OF C OMPLIANCE ......................................................................................6-3
6.4.2 E NERGY AND N ON

- AIR I MPACTS ........................................................................6-3
6.4.3 R EMAINING U SEFUL L IFE ...................................................................................6-4 

### 6.5 E VALUATE 

### V ISIBILITY 

### I MPACTS 

### ........................................................................... 6-4 6.6 P ROPOSED 

### B ART FOR 

### NO X 

### .................................................................................... 6-4

A PPENDIX 

### A

– E MISSION 

### E STIMATES



### A PPENDIX 

### B

- E CONOMIC 

### A NALYSES



### A PPENDIX 

### C

– CALPUFF M ODELING 

### P ROTOCOL



### A PPENDIX 

### D

– M ODELING 

### I NPUT 

### /O UTPUT 

### F ILESAEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 ii 

## L IST OF 

## F IGURES

T ABLE 3-1. C ONSTRUCTION D ATE S UMMARY ...................................................................................3-1

T ABLE 3-2. P RE -BART E MISSIONS S UMMARY ..................................................................................3-1

T ABLE 3-3. PM S PECIATION P ROFILE .................................................................................................3-2

T ABLE 3-4. S PECIATED PM E MISSIONS ..............................................................................................3-2

T ABLE 3-5. P OINT S OURCE S TACK P ARAMETERS ..............................................................................3-3

T ABLE 4-1. B ASELINE M AXIMUM 24-H OUR A VERAGE SO 2 E MISSION R ATES ..................................4-1

T ABLE 4-2. A VAILABLE SO 2 C ONTROL T ECHNOLOGIES ....................................................................4-1

T ABLE 4-3. SO 2 E MISSION E STIMATES (N ATURAL G AS )....................................................................4-2

T ABLE 5-1. B ASELINE M AXIMUM 24-H OUR A VERAGE PM E MISSION R ATES ...................................5-1

T ABLE 5-2. A VAILABLE PM C ONTROL T ECHNOLOGIES .....................................................................5-1

T ABLE 5-3. PM E MISSION E STIMATES ................................................................................................5-1

T ABLE 6-1. B ASELINE 24- HR A VERAGE NO X E MISSION R ATES .........................................................6-1

T ABLE 6-2. A VAILABLE NO X C OMBUSTION C ONTROL T ECHNOLOGIES ............................................6-1

T ABLE 6-3. C ONTROL E FFECTIVENESS OF T ECHNICALLY F EASIBLE NO X C ONTROL T ECHNOLOGIES 6-2

T ABLE 6-4. NO X C ONTROL C OSTS S UMMARY ...................................................................................6-3

T ABLE 6-5. C OMANCHE U NIT 1G1 AND 1G2 V ISIBILITY I MPACTS (NO X ).........................................6-4AEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 1-1 

## 1. E XECUTIVE 

## S UMMARY

American Electric Power/Public Service Comp any of Oklahoma (AEP/PSO) owns and operates the Comanche Power Station, located near Lawton, OK. The Comanche station is an electricity generating station that primarily consists of tw o natural-gas fired combustion turbines with duct burners and heat recovery steam generators (HRSGs). The Comanche Station is a Title V major source of emissions and currently operates under Permit No. 2003-261-TVR, issued April 21, 2006.

Based upon the construction date of the sources at th e Comanche station, AEP has determined that both units are eligible to be regulated under the Best Available Retrofit Technology (BART) provisions of the U.S. Environmental Protection Ag ency’s (EPA) Regional Ha ze Rule as established in Title 40, Code of Federal Re gulations Part 51 (40 CFR 51). Both turbine/duct burner units comprise the BART-eligible source at the Comanche Station.

In addition, AEP has determined that the Comanc he Station contributes greater than 0.5 deciviews ( ∆ dv) to visibility impairment in a federally pr otected Class I area when compared to a natural background. As a result, it does not qualify for exem ption and is subject to a BART determination. Per the guidelines in 40 CFR Part 51 1 , a BART determination for SO 2 , NO X , and PM was performed using the five-step analysis that included the following:

1. Identifying all available retrofit control technologies;

2. Eliminating technically infeasible control technologies;

3. Evaluating the control effectiveness of remaining control technologies;

4. Evaluating impacts and document the results;

5. Evaluating visibility impacts

Based on the five-step analysis, AEP proposes the following as BART:

• PM – AEP proposes the use of natural gas at the Comanche Station as BART for PM. Natural gas use is able to ensure PM emi ssions lower than add-on PM controls.

• SO 2 – AEP also proposes the use of natural gas at the Comanche Station as BART for SO 2
. As with PM emissions, natural gas use is able to ensure SO 2 emissions lower than add-on SO 2 controls.

• NO X – AEP proposes emission rates of 0.15 lb/MMBtu as BART for NOx. This will be achieved by retrofitting the turbines with Dry Low NOx burners (DLNB).

1 40 CFR 51, Regional Haze Regulations and Guidelines for Best Available Retrofit Technology (BART) DeterminationsAEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 2-1 

## 2. B ACKGROUND

On July 1, 1999, the U.S. Environmental Protec tion Agency (EPA) published the final Regional Haze Rule (RHR). The objective of the RHR is to impr ove visibility in 156 specific areas across the United States, known as Class I areas. The Clean Air Act defines Class I areas as certain national parks (over 6,000 acres), wilderness areas (over 5,000 acres), national memorial parks (over 5,000 acres), and international parks that were in existence on August 7, 1977.

On July 6, 2005, the EPA published amendments to its 1999 RHR, often called the BART rule, which included guidance for making source-specific B est Available Retrofit Technology (BART) determinations. The BART rule defines BART-e ligible sources as sources that meet the following criteria:

(1) Have potential emissions of at least 250 tons per year of a visibility-impairing pollutant, (2) Were “in existence” between August 7, 1962 and August 7, 1977, and (3) Are listed as one of the 26 listed source categories in the guidance.

A source that meets these criteria is considered elig ible for BART and must then determine if BART applies.



## 2.1 BART A PPLICABILITY

Per the U.S. EPA’s BART Modeling Guidance, “an individual source will be considered to ‘cause visibility impairment’ if the emissi ons results in a change (delta ∆ ) in deciviews (dv) 2 that is greater than or equal to 1.0 deciview on the visibility in a Class I area...if the emissions from a source results in a change in visibility that is greater than or equal to 0.5 dv in a Class I area the source will be considered to ‘contribute to visibility impairment .’” To determine whether a BART-eligible source causes or contributes to visibility impairment, the U.S. EPA guidance requires the use of an air quality model, specifically recommending the CALPUFF modeling system, to quantify the impacts attributable to a single BART-eligible source. Because contribution to visibility impairment is sufficient cause to require a BART determination, 0.5 dv is the critical threshold for assessment of BART applicability.

Regional haze is quantified using the light extinction coefficient ( b ext ), which is expressed in terms of the haze index ( HI ) expressed in dv. The HI is calculated as shown in the following equation.

       

= 10 ln 10 ext b HI

The impact of a BART-eligible source is determined by comparing the HI attributable to a source to estimated natural background conditions. That is, a single-source visibility impact is measured as the

2 The deciview (dv) is a metric used to represent norma lized light extinction attributable to visibility-affecting pollutants.AEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 2-2 change in light extinction versus background, and is referred to as ∆ dv. The background extinction coefficient is affected by various chemical sp ecies and the Rayleigh scattering phenomenon and can be calculated as shown in the following equation.



# ( ) Ray EC Coarse Soil OC NO SO background ext b b b b b b b b + + + + + + = −

3 4 1

, Mm

where:



### ( ) 

## [ ] ( ) 

### [ ] ( ) 

### [ ] [ ] [ ] [ ] 

# ( ) ( ) 

### [ ] 3 1 3 4 4

2 4

m μg in ion Concentrat Function Humidity Relative default by Mm 10 Scattering Rayleigh

EC 10 Mass Coarse 6

. 0 Soil 1 OC 4 NO

NH 3 SO

NH 3

3 4

= =

= = = = = = =

−

RH f b b b b b RH f b RH f b

Ray

EC Coarse Soil OC NO SO 

### ( ) 

## [ ] [ ] [ ] [ ] [ ] [ ]

molecules air to due scattering is Scattering Rayleigh carbon elemental of ion concentrat the denotes EC dusts coarse of ion concentrat the denotes Mass Coarse soils fine of ion concentrat the denotes Soil carbon organic of ion concentrat the denotes OC ion concentrat nitrate ammonium the denotes NO NH ion concentrat sulfate ammonium the denotes SO NH

3 4 4 2 4

Values for the parameters listed above specific to the natural background conditions at each Class I area are provided on an annual-average basis in the U.S. EPA’s Guidance for Estimating Natural Visibility Conditions under the Regional Haze Rule

. 3

Particulate species that affect visibility are em itted from anthropogenic (human-caused) sources and include coarse particulate matter (PMC), fine partic ulate matter (PMF), and elemental carbon (EC) as well as precursors to secondary organic aerosols (SOA) and fine particulate matter such as SO 2 and
NO X . The extinction coefficient due to emissions of visibility-affecting pollutants from a single BART-eligible source is calculated according to the following equation. 

# ( )

EC PMC PMF SOA NO SO source ext b b b b b b b + + + + + = −

3 4 1

, Mm

where:

3 U.S. EPA, Guidance for Estimating Natural Visibility Conditions Under the Regional Haze Rule , Table 2-1, Attachment A, September 2003, EPA-454/B-03-005.AEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 2-3 

### ( ) 

## [ ] ( ) 

## [ ] ( ) 

## [ ] [ ]

[ ] [ ] ( ) 

## [ ] 3 3 4 3 4 2 4 4

m μg in ion Concentrat Function Humidity Relative EC 10 PMC 6

. 0 PMF 1 SOA 4 NO

NH 3 SO

NH 3

= =

=

= = = = =

RH f b b b b RH f b RH f b

EC

PMC PMF SOA NO SO 

### ( ) 

## [ ] [ ] [ ] [ ] [ ] [ ] carbon elemental of ion concentrat the denotes EC PM coarse of ion concentrat the denotes PMC PM fine of ion concentrat the denotes PMF aerosols organic secondary of ion concentrat the denotes SOA ion concentrat nitrate ammonium the denotes NO NH ion concentrat sulfate ammonium the denotes SO NH

3 4 4 2 4



### 2.1.1 CALPUFF M ODELING 

### A NALYSES

As stated above, the BART Guidelines r ecommend using the CALPUFF modeling system to compute the 24-hour average visibility impa irment attributable to a BART-eligible source to assess whether the 0.5 ∆ dv contribution threshold is exceeded, and if so, the frequency, duration, and magnitude of any exceed ance events. As descr ibed further in the modeling protocol included in Appendix A, CALPUFF is a refined air quality modeling system that is capable of simulating the di spersion, chemical transformation, and longrange transport of multiple visibility-affecting pollutant emissions and is therefore preferred for BART applicability and determination analyses.



## 2.2 BART D ETERMINATION

BART-eligible sources that are found to cause or contribute to visibility impairment at a Class I area are required to make a BART determination. The BART Guidelines define BART as follows:

BART means an emission limitation based on th e degree of reduction achievable through the application of the best system of continuous emission reduction for each pollutant which is emitted by...[a BART-eligible s ource]. The emission limitation must be established, on a case-by-case basis, taking in to consideration the technology available, the costs of compliance, the energy and non-air quality environmental impacts of compliance, any pollution control equipment in use or in existence at the source, the remaining useful life of the source, and the de gree of improvement in visibility which may reasonably be anticipated to result from th e use of such technology. The BART analysis identifies the best system of continuous emission reduction taking into account:

(1) The available retrofit control options, (2) Any pollution control equipment in use at the source (which affects the availability of options and their impacts), (3) The costs of compliance with control options, (4) The remaining useful life of the facility, (5) The energy and non-air quality environmental impacts of control options [ , and ] (6) The visibility impacts analysis.AEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 2-4 Further, the BART rule indicates that the five b asic steps in a BART analysis can be summarized as follows:

1. Identify all available retrofit control technologies;

2. Eliminate technically infeasible control technologies;

3. Evaluate the control effectiveness of remaining control technologies;

4. Evaluate impacts and document the results;

5. Evaluate visibility impacts

As summarized in Section 3, AEP conducted a BART applicability analysis for the three units at the Comanche Station and determined that the units ar e subject to BART. The BART determinations for each of the three visibility affecting pollutants (SO 2 , NOx, and PM) can be found in Sections 4 through 6.AEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 3-1 

## 3. BART A PPLICABILITY 

## A NALYSIS



## 3.1 BART-E LIGIBLE 

## S OURCES

In order to determine what specific units constitu te the “BART-eligible” source, the construction dates of the each of the plant’s units must be ex amined. A summary of all units at the Comanche Station is provided below. As seen from this tabl e, both turbine/duct burner units were “in existence” within the 15-year BART window (August 7, 1962-August 7, 1977).

T ABLE 3-1. C ONSTRUCTION D ATE S UMMARY

Unit
No. Heat Duty (MMBtu/hr) Manufacturer/Model Construction Date

1G1 1,250 Westinghouse/W-501B May 1971 1G2 1,250 Westinghouse/W-501B May 1971 DB1 200 Westinghouse Steam Generator Burner May 1971 DB2 200 Westinghouse Steam Generator Burner May 1971



## 3.2 S OURCE 

## E MISSIONS 

## D ATA

In developing baseline emissions, Trinity utilized a combination of operating records and continuous emission monitoring (CEM) data provided by AEP over a period extending from 2001-05. Modeled emissions are based on the highest hourly emissi on rate (on 24-hour calendar day average) that occurred from 2001 to 2005. A summary of these emissi ons is presented in Table 3-2 below. A more detailed analysis of historical em issions is included in Appendix A.

T ABLE 3-2. P RE -BART E MISSIONS S UMMARY

Unit No. NO x PM SO 2 H 2 SO 4 lbs/hr lbs/hr lbs/hr lbs/hr
1G1 870.00 8.25 0.75 0.11
1G2 766.30 8.25 0.75 0.11

Both turbines operated on natural gas during the 2001- 05 period. In addition, the duct burners havenot operated for several years, and not over the 2001-05 period. As a result, separate listing of preBART baseline emissions is not included. As discu ssed in the cover letter accompanying this report, AEP did not include the duct burners in this analysis.AEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 3-2 

### 3.2.1 PM E MISSIONS

PM emissions are not directly entered into the model but are instead speciated into constituent components. The PM emissions from the boilers can be speciated according to the Federal Land Managers’ guidance to potentially include the following:

S Coarse particulate matter (PM C , considered PM 2.5-10 )

S Fine particulate matter (PM F , considered PM <2.5 )

S Sulfates (SO 4 )

S Secondary organic aerosols (SOA)

S Elemental carbon (EC)

Based upon FLM guidance, PM emissions from natural gas combustion consists of primarily coarse (25%) and fine (75%). 4 A summary of speciated PM emissions is presented in Table 3-3 below.

T ABLE 3-3. PM S PECIATION P ROFILE

Particulate Matter Species Fraction PM Coarse (Soil) 25% Elemental Carbon (EC) 0%
PM Fine 75% Secondary Organic Aerosols (organic carbon) 0%

Total 100%

A summary of speciated PM emissions from the Comanche units is presented below.

T ABLE 3-4. S PECIATED PM E MISSIONS

Unit No. PM (coarse) 4 PM (fine) 4 EC 4 SOA 4

lbs/hr lbs/hr lbs/hr lbs/hr 1G1 2.06 6.19 0 0
1G2 2.06 6.19 0 0



### 3.2.2 S TACK PARAMETERS

Table 3-5 provides a summary of source exhaust parameters.

4 http://www2.nature.nps.gov/air/ Permits/ect/ectGasFiredCT.cfmAEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 3-3 T ABLE 3-5. P OINT S OURCE S TACK P ARAMETERS

Emission
unit Latitude (decimal degrees) Longitude (decimal degrees) Exit Velocity

(ft/s) Stack Height (feet) Stack
Diameter (feet) Exit Temperature (Fahrenheit)
1G1 34.5434 98.3243 147 53 10.2 355 1G2 34.5432 98.3243 147 53 10.2 355

The base elevation of each of the units is 338 meters (1,108 feet) above MSL based upon visual inspection of USGS topographic maps.AEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 4-1 

## 4. SO 2 

## BART D ETERMINATION

A summary of pre-BART SO 2 emissions over the 2001-05 time period as described in Section 3 is included below.

T ABLE 4-1. B ASELINE M AXIMUM 24-H OUR A VERAGE SO 2 E MISSION R ATES

Emission
Unit SO 2 Emission Rate (lb/hr)
1G1 0.75
1G2 0.75



## 4.1 I DENTIFICATION OF 

## A VAILABLE 

## R ETROFIT 

## SO 2 

## C ONTROL 

## T ECHNOLOGIES

The first step of a BART determination is the identification of all available retrofit SO 2 control technologies. A list of control technologies was obtained by reviewing the U.S. EPA’s Clean Air Technology Center, control equipment vendor information, publicly-available air permits, applications, and BART analyses, and technical literature published by the U.S. EPA and Regional Planning Organizations (RPOs).

T ABLE 4-2. A VAILABLE SO 2 C ONTROL T ECHNOLOGIES

SO 2 Control Technologies

Dry Sorbent Injection Spray Dryer Absorber (SDA) i.e., Semi-Dry Scrubber Wet Scrubber Circulating Dry Scrubber (CDS)

All of the technologies listed in Table 4-2 involve removing the SO 2 in the exhaust gas, which is known as flue gas desulfurization (FGD). AEP prop oses to restrict fuel usage at the Comanche Station to natural gas only. Commercial-grade natura l gas is intrinsically low in sulfur content, and results in low sulfur emissions. The facility’s existing Title V operating pe rmit (No. 2003-261-TVR) provides an estimate of SO 2 emissions from the combustion of natural gas, as summarized below.AEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 4-2 T ABLE 4-3. SO 2 E MISSION E STIMATES (N ATURAL G AS )

SO 2 Emission
Unit lb/hr TPY

1G1 4.25 18.62

1G2 4.25 18.62

SO 2 emissions from the two Comanche units are suffi ciently low from natural gas usage that no addon control technology could be considered economically feasible. As a result, AEP determines that natural gas usage is SO2 BART for the Comanche units.AEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 5-1 

## 5. PM BART D ETERMINATION

A summary of pre-BART PM emissions over the 2001-05 time period as described in Section 3 is included below.

T ABLE 5-1. B ASELINE M AXIMUM 24-H OUR A VERAGE PM E MISSION R ATES

Emission
Unit PM Emission Rate (lb/hr)
1G1 8.25
1G2 8.25



## 5.1 I DENTIFICATION OF 

## A VAILABLE 

## R ETROFIT 

## PM C ONTROL 

## T ECHNOLOGIES

The first step of a BART determination is the id entification of all available retrofit PM control technologies. A list of control technologies was obtained by reviewing the U.S. EPA’s Clean Air Technology Center, control equipment vendor information, publicly-available air permits, applications, and BART analyses, and technical literature published by the U.S. EPA and Regional Planning Organizations (RPOs).

T ABLE 5-2. A VAILABLE PM C ONTROL T ECHNOLOGIES

PM Control Technologies
Electrostatic Precipitator (wet or dry) Baghouse (Fabric Filter)

AEP proposes to restrict fuel usage at the Comanc he Station to natural gas only. As with SO 2 , the use of commercial-grade natural inherently results in low particulate emissions. The facility’s existing Title V operating permit (No. 2003-261-TVR) provides an estimate of PM emissions from the combustion of natural gas, as summarized below.

T ABLE 5-3. PM E MISSION E STIMATES

PM Emission
Unit lb/hr TPY

1G1 8.25 36.14

1G2 8.25 36.14AEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 5-2 These emission estimates for these two Comanche units from natural gas usag e are sufficiently low that no add-on control technology could be considered economically feasible. As a result, AEP determines that natural gas usage is BA RT for PM for the Comanche units.AEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 6-1 

## 6. NO X 

## BART D ETERMINATION

The highest 24-hr average pre-BART NO X emissions over the 2001-05 time period are summarized in Table 6-1.

T ABLE 6-1. B ASELINE 24- HR A VERAGE NO X E MISSION R ATES

Unit ID NO X Hourly Emission Rate NO X Emission Rate (lb/hr) (lb/MMBtu) 1G1 870.0 0.696
1G2 766.3 0.613



## 6.1 I DENTIFY 

## A LL 

## A VAILABLE 

## R ETROFIT 

## T ECHNOLOGIES

Step 1 of the BART determination is the identification of all available retrofit NO X control technologies. For gas-fired applications, the Fedreal Rule at 40 CFR Part 51, Regional Haze Regulations and Guidelines for BART Determinati ons: Final Rule (70 Fed. Reg. July 6, 2005) indicates use of “current combustion technology” as BART. A list of “current combustion control” technologies, as applicable to the Gas- Tturbines, was obtained by reviewing the U.S. EPA’s Clean Air Technology Center, control equipment vendor information, publicly -available air permits, applications, and BART analyses, and technical litera ture published by the U.S. EPA and the RPOs.

T ABLE 6-2. A VAILABLE NO X C OMBUSTION C ONTROL T ECHNOLOGIES

NO X Control Technologies

Dry Low NOx Burners (LNB)

As listed in Table 6-2, NO X emissions controls for the Comanche Power Station gas turbines based on “current combustion control technology” is limite d to Dry Low NOx Burners. Site specific considerations and marginal perform ance results of approaches such as water or steam injection did not merit their consideration as control possibilities.



## 6.2 E LIMINATE 

## T ECHNICALLY 

## I NFEASIBLE 

## O PTIONS

Step 2 of the BART determination is to eliminate technically infeasible NO X control technologies that were identified in Step 1. In the case of the Comanc he Power Station Units 1 and 2, the site specific applicable NOx control was limited to Dry Low NOx Burners and water or steam injection were considered inappropriate.AEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 6-2 

### 6.2.1 D RY 

### L OW 

### NO X 

### B URNERS 

### (DLNB)

LNB technology utilizes advanced burner design to reduce NO X formation through the restriction of oxygen, lowering of flame temperature, and/or reduced residence time. LNB is a staged combustion process that is designed to split fuel combustion into two zones. In the primary zone, NO X formation is limited by either one of two methods. Under staged fuel-rich conditions, low oxygen levels limit flame temperatures resulting in less NO X formation. The primary zone is then fo llowed by a secondary zone in which the incomplete combustion products formed in th e primary zone act as reducing agents. Alternatively, under staged fuel-lean cond itions, excess air will reduce flame temperature to reduce NO X formation. In the secondary zone , combustion products formed in the primary zone act to lower the local oxygen concentration, resulting in a decrease in NO X formation. When utilized in new turbine d esigns, reductions of up to 60 percent may result. 5 A similar level of effectiveness is exp ected with retrofit installations. This technology is considered a technically feasible option.

.



## 6.3 E VALUATE 

## E FFECTIVENESS OF 

## R EMAINING 

## C ONTROL 

## T ECHNOLOGIES

The third step in the BART analysis is to rank the technically feasible options according to effectiveness.

T ABLE 6-3. C ONTROL E FFECTIVENESS OF T ECHNICALLY F EASIBLE NO X C ONTROL T ECHNOLOGIES

Control Technology Estimated Control Efficiency (%)

Dry Low NOx Burners ~30-60

Installation of dry low NOx burners is expected to allow the turbines to attain an emission level of 0.15 lb NOx/MMBtu..



## 6.4 E VALUATION OF 

## I MPACTS FOR 

## F EASIBLE 

## NO X 

## C ONTROLS

Step four for the BART analysis procedure is the impact analysis. The BART determination guidelines list four factors to be considered in the impact analysis:

▲ Cost of compliance
▲ Energy impacts
▲ Non-air quality impacts; and
▲ The remaining useful life of the source

Evaluation of a fifth factor, visibility impacts, is addressed separately in Section 6.5.

5 "Assessment of Control Technology Options for BART -Eligible Sources: Steam Elec tric Boilers, Industrial Boilers, Cement Plants and Paper and Pulp Facilities" Northe ast States for Coordinated Ai r Use Management (NESCAUM), March 2005AEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 6-3 

### 6.4.1 C OSTS OF 

### C OMPLIANCE

Per the BART Guidelines, the costs of complianc e analysis for each cont rol option consists of comparisons of the average cost effectiveness and the incremental cost effectiveness, which are defined in Section IV.D.4 as follows:

Average cost effectiveness means the total an nualized costs of control divided by the annual emissions reduction (the differen ce between baseline annual emissions and the estimate of emissions after controls), using the following formula:

Average cost effectiveness (dollars per t on removed) = Control option annualized cost ÷ (Baseline annual emissions – Annual emissions with Control option)

...the incremental cost effectiveness calcul ation compares the costs of performance level of a control option to those of the n ext most stringent option, as shown in the following formula (with respect to cost per emissions reduction):

Incremental Cost Effectiveness (dollars per incremental ton removed) = (Total annualized costs of control option) – (Total annualized costs of next control option) ÷ (Control option annual emissions) – (Next control option annual emissions)

Capital costs associated with implementing the evaluated control systems were provided to AEP by an after-market vendor. A detailed su mmary of those costs is included in Appendix B, while estimates of annual pollutant reducti ons for the evaluated control technologies are included in Appendix A. The average cost effectiveness of this control options is summarized in Table 6-4. Please note that since no other options were examined, incremental cost effectiveness is not relevant (and not included).

T ABLE 6-4. NO X C ONTROL C OSTS S UMMARY

Average Cost
Effectiveness Incremental Cost
Effectiveness Emission Unit Control Strategy $/ton $/ton 1G1 and 1G2 Dry low NOx

Burners 2,600 --



### 6.4.2 E NERGY AND 

### N ON



### - AIR 

### I MPACTS

Energy and non-air impacts from DLNB retrofit are minimal. AEP expects that the retrofit will have a limited derating impact on the turbines, resulting in a total output decrease of 1-
2%.AEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 6-4 

### 6.4.3 R EMAINING 

### U SEFUL 

### L IFE

The remaining useful life of the Comanche units do not impact the annualized capital costs of potential controls because the useful lives of the units are anticipated to be at least as long as the capital cost recovery period, which is 20 years.



## 6.5 E VALUATE 

## V ISIBILITY 

## I MPACTS

In order to determine the change in visibilit y impact from the various NOx control options considered, calculated emissions were modeled in CALPUFF. As discussed in the modeling protocol included in Appendix A, visibility impacts were eval uated each of the four nearby Class I areas.

Pre-BART baseline emissions for each unit are mode led and summarized below. Subsequent control scenarios incorporated calculated NOx emissions fro m post-control scenarios, and incorporated all other pollutants at baseline emissions. Per BART determination procedures, visibility impacts are presented below on a unit-by-unit basis.

T ABLE 6-5. C OMANCHE U NIT 1G1 AND 1G2 V ISIBILITY I MPACTS (NO X )

Class I area 98 th Percentile Impact Pre-BART DLNB Visibility Improvement ∆ dv ∆ dv Caney Creek 0.097 0.022 77% Hercules-Glades 0.068 0.015 78% Upper Buffalo 0.078 0.017 78% Wichita Mountains 1.776 0.438 75%



## 6.6 P ROPOSED 

## B ART FOR 

## NO X

AEP has determined that the NO X BART for each of the Comanche units is DLNB. Based upon the modeled visibility improvement and calculated averag e cost effectiveness, this control option cannot be considered either technically or economically infeasible. Based upon DLNB control effectiveness estimates, AEP proposes a BART NOx emission rate of 0.15 lb/MMBtu.AEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 

## A PPENDIX 

## A

– E MISSION 

## E STIMATESUnit 1G1PM (filterable)3PM (condensible)3lb/mmBtu lb/hr lb/mmBtu lb/hr lb/mmBtu lb/hr lb/mmBtu lb/hr lb/hr lb/hrCase 1 Baseline Case -- 0.696 870.0 0.0006 0.75 -- 0.11 0.0066 8.25 2.06 6.19Case 2 DLNB 78% 0.150 187.5 0.0006 0.75 -- 0.11 0.0066 8.25 2.06 6.19Unit 1G2PM (filterable)3PM (condensible)3lb/mmBtu lb/hr lb/mmBtu lb/hr lb/mmBtu lb/hr lb/mmBtu lb/hr lb/hr lb/hrCase 1 Baseline Case -- 0.613 766.3 0.0006 0.75 -- 0.11 0.0066 8.25 2.06 6.19Case 2 DLNB 76% 0.150 187.5 0.0006 0.75 -- 0.11 0.0066 8.25 2.06 6.191H2SO4emissions based upon the following assumptions:SO2Conversion to SO3= 10%SO3Conversion to H2SO4= 100%MW H2SO4= 98 lb/lbmolMW SO2= 64 lb/lbmolSample Calculation:0.75 lb SO2 lbmol 0.1 lbmol SO3 1 lbmol H2SO4 98 lb H2SO4 = 0.11 lb SO4hr 64 lb SO2 lbmol SO2 lbmol SO3 lbmol hr2Baseline emission data for PM is not available. PM Emission Factor obtained from AP-42 (4/2000), Table 3.1-2a, Stationary Gas TurbinesPlease note that for natural gas usage, PM10 emissions can be considered equivalent to total PM.PM10= 0.0066 lb/MMBtu3Condensible/filterable PM speciation were based on the following profiles:For Natural Gas fired combustion turbines. http://www2.nature.nps.gov/air/Permits/ect/ectGasFiredCT.cfmFilterable 25.00%Condensible 75.00%4NOx control estimate for DLNB provided to AEP by Siemens Westinghouse. See emails dated 8/8/2008 and 8/13/2008 [Controlled emission rates for NE2-SW3_Comanche.xls]PM (total)NOx SO2PM10SpeciationComanche Power StationSO4(from SO2)1SO4(from SO2)PercentReductionPercentReductionPM10Speciation24-hour Average Emission EstimatesPM (total)2NOx SO2American Electric PowerComanche Power StationEmission Estimates (lbhr)Printed on 8/27/2008Page 1 of 2Trinity Consultants083701.0057Unit 1G1NOx% reductionlb/mmBtu1tpyCase 1 Baseline Case -- 0.480 2,628Case 2 DLNB 69% 0.150 821Unit 1G2NOx% reductionlb/mmBtu1tpyCase 1 Baseline Case -- 0.460 2,519Case 2 DLNB 67% 0.150 8211Baseline emission factor based upon annual average. Provided by AEP via email, 8/20/20081G11G212501250Comanche Power StationAnnual Emission EstimatesUnit IDMaximum Heat Duty(MMBtu/hr)American Electric PowerComanche Power StationEmission estimates (Annual)Printed on 8/27/2008Page 2 of 2Trinity Consultants083701.0057Comanche StationCALPUFF Visibility ResultsPeak Impact 98th PercentilePollutant Class I AreaControlTechnology (∆dv)% Reductionfrom previous% Reductionfrom Baseline (∆dv)% Reductionfrom previous% Reductionfrom BaselineNOx Caney Creek Baseline 0.720 -- -- 0.097 -- --DLNB 0.167 77% 77% 0.022 77% 77%Herc-Glades Baseline 0.224 -- -- 0.068 -- --DLNB 0.051 77% 77% 0.015 78% 78%Upper Buffalo Baseline 0.275 -- -- 0.078 -- --DLNB 0.062 77% 77% 0.017 78% 78%Wichita Mts Baseline 5.585 -- -- 1.776 -- --DLNB 1.608 71% 71% 0.438 75% 75%PM10Caney Creek Baseline 0.001 -- -- -- -- --Herc-Glades Baseline -- -- -- -- -- --Upper Buffalo Baseline 0.001 -- -- -- -- --Wichita Mts Baseline 0.054 -- -- 0.023 -- --SO2Caney Creek Baseline 0.001 -- -- -- -- --Herc-Glades Baseline -- -- -- -- -- --Upper Buffalo Baseline -- -- -- -- -- --Wichita Mts Baseline 0.010 -- -- 0.004 -- --AEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 

## A PPENDIX 

## B

- E CONOMIC 

## A NALYSESPrinted: 8/29/2008

Economic Analysis for Dry Low NOx Burners

Capital Cost Summary Capital Cost

TOTAL CAPITAL INVESTMENT a TCI = $34,660,000

Annual Cost Summary Annual Cost

DIRECT OPERATING COSTS Low-NOx burners are not expected to incur any additional significant direct operating costs

TOTAL DIRECT COSTS (DC) DC = $0

INDIRECT OPERATING COSTS Administrative Charges (2% of TCI) b $693,200

Insurance (1% of TCI) b $346,600

Property Taxes (1% of TCI) b $346,600

Capital Recovery (CRF x TCI) 20 years @ 8.00% interest CRF = 0.1019 $3,530,198

TOTAL INDIRECT COSTS (IC) IC = $4,916,598

TOTAL ANNUALIZED COST (TAC = DC + IC) TAC= $4,916,598

Cost Effectiveness Summary

Annual Control Cost: $4,916,598

NOx to be Removed (tpy): c 1,891

CONTROL COST EFFECTIVENESS ($/ton): $2,600

a Cost data provided by AEP (8/19/2008). Cost listed above is the total for both Comanche turbines b Direct and indirect cost factors taken from OAQPS Control Cost Manual, Sixth Edition, January 2002. c NOx total includes reductions from both turbines: Unit 1G1 Unit 1G2 DLNB NOx Removal Rate = 69% 67% Annual Capacity Factor = 0.53 0.55 Provided by AEP via email, 8/20/2008 Baseline (pre-BART) emission factor = 0.48 0.46 Based upon an annual average Maximum Firing Rate = 1250 1250 MMBtu/hr, as listed in Permit No. 96-288-TV.

Sample Calculation (Unit 1G1):

0.48 lb 1250 MMBtu 8760 hrs ton 0.53 capacity factor 0.69 NOx Removal Rate = 957.58 tons NOx MMBtu hr yr 2000 lb year

American Electric Power Comanche Power Station Cost Analysis (DLNB) Trinity Consultants
083701.0057AEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 

## A PPENDIX 

## C

– CALPUFF M ODELING 

## P ROTOCOLAEP Trinity Consultants Comanche Power Station Units 1 and 2 083701.0057 

## A PPENDIX 

## D

– M ODELING 

## I NPUT 

## /O UTPUT 

## F ILES



### Control Scenario Description Model Run Number
NOx SO 2

Case 1 Baseline Case Run 1 Run 1

Case 2 DLNB Run 2 --